WO 01/89885 discloses a device for implementing an element, particularly a security element, for the protection of goods and/or persons and especially for the protection of at least one occupant of a vehicle, of the type comprising a gas generating system connected to the security element, for example, an inflatable safety cushion, and comprising an explosive charge formed at least by a primary pyrotechnic compound and a secondary compound. In that system, the primary pyrotechnic compound is intended to steer decomposition of the secondary compound and permits at least one interaction of the combustion products of the primary and secondary compound(s) in at least one unconfined or weakly confined interaction volume of the gas generating system, where the interaction may at least partially be, in particular, an oxidation-reduction reaction.
The gas generation system according to WO 01/89885 is different from other systems as for instance a simple effect generator such as the one described in U.S. 2003/0051630 or a double effect generator such a the one described in U.S. Pat. No. 6,149,193, particularly due to the fact that the decomposition of the secondary compound is driven by the primary compound.
The composition envisaged in that disclosure is satisfactory, but the device has the principal disadvantage of giving off a considerable amount of nitrogen oxides. Furthermore, that composition, or a composition of that type, brings about the formation of much water, which after condensing is detrimental to the gas yield. Moreover, that composition requires the consumption of all the oxygen present in the ammonium nitrate, so that at least 40% of propellant has to be included in the composition.